Download Genes and Cell Division

Heredity and the Origin of Life
Genes and Cell Division
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____________________ – the cell’s “blueprints”;
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they contain the information needed to build ___________ and cell products.
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Genes are stored in the __________________________ (just like blueprints
would be stored in a filing cabinet in a factory).
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_______________________ (like filing cabinets) - are found in the
___________________ (like in the file room).
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Each cell contains a ___________________ set of all the organism’s genes.
______________ Division – aka “binary fission”, occurs when one cell (parent
cell) divides to produce __________ new cells (daughter cells).
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Can be compared to building a new factory exactly like the old one.
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In order to build, you have to have a plan and an order of steps.
A cell goes through __________________ stages to prepare and finally divide into
two new cells
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Three stages of cell division
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First Stage: _________________________
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Stage where genes are copied
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Genes are on long, thin chromosomes
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Sister ____________________________ – two identical strands
Second Stage: _________________________
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The equal distribution of the parent cell’s genes
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Four phases of ______________________:
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____________________
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Membrane around nucelus disappears
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Sister chromatids attached and spindle fibers form
____________________
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____________________
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All chromosomes line up in middle
Each pair separates and move to opposing ends
____________________
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Reach each end and begin to uncoil; form two new
nuclei
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Third Stage: ________________________
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________________ stage of cell division
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Divides each daughter cell with some cytoplasm and
organelles
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The parent cell pinches in between the two nuclei until
cytoplasm divides
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The purpose of mitotic cell division is to insure that each new daughter cell
has genes __________________________ to those in the parent cell.
Asexual Reproduction: A result of mitotic cell division
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________________________ reproduction – reproduction by
____________________ cell divisions.
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Types of asexual reproduction:
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__________________ – a method of asexual reproduction illustrated by
yeast
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__________________ – process of re-growing missing parts.
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The bulge is called a “bud”
Examples: planarians, lizard tail, starfish arms.
__________________ – a cell surrounded by a protective coating
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Example: Bread mold
Sexual Reproduction
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Occurs when ________________ organisms each give a complete copy of their
genes to form a new organism.
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______________________ - when copies of genetic information during sexual
reproduction are produced
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During meiosis, the genetic material is _________________________ just as
in mitosis, but there is an additional step, where the daughter cells divide,
making _____________ total instead of _______________.
Heredity and the Origin of Life
How Genes Function
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There is a specific “________________________” of genes.
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In this language, four symbols are called ___________________________.
Adenine, Thymine, Guanine, Cytosine – A, T, C, G – in DNA
Adenine, Uracil, Guanine, Cytosine – A, U, C, G – in RNA
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Letters are made out of ________ nucleotides and are called __________
Example codon: AGC
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Words made from the __________ are called _____________.
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These “words” can even be translated into another language – the language of
protein.
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Symbols A,T,G,C (_________________________)
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Letters (________________)
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Words (________________)
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Four main points to keep in mind:
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_________________________ (symbols) are arranged into
__________________ (words)
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________________ are arranged into ___________________(words)
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Genes are _________________________ for making proteins
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During reproduction, a _________________________ copy is made of all
genes and is given to ______________ new organism
DNA is coded messages
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1953 __________________________________________ – discovered and worked
out the model for ________________ (deoxyribonucleic acid)
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______________ – looks like a twisted ladder and it is made up of units called
nucleotides
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There are four different________________________ and EACH contains a
______________, phosphate, and _________________
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_________________
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_________________
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_________________
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_________________
In DNA, _______________________are arranged so that the sugars and phosphates
form the sides of the ladder while the bases make up the rungs of the ladder (See
page 86-87 in your text)
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____ always pairs up with T
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____ always pairs up with G
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___________________ – they are specific sections of DNA
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_____________________________ – the process by which one DNA molecule forms
two DNA molecules
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This occurs before a cell divides
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See p. 87 for process (and handout)
RNA helps decode the messages
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DNA contains genetic information in a _________________
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The code is an arrangement of _____________ in the DNA molecule
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When a cell needs a certain protein, the section of __________ (gene) for that
protein makes ribonucleic acid (__________)
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RNA is different from DNA in its bases; _______________ is replaced by
______________
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_________ – messenger RNA; because the RNA contains a copy of the DNA’s coded
message
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______________________ – process of making mRNA molecule
The Decoded messages are Proteins
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After mRNA is made in the ________________, it carries a working copy of DNA’s
coded message to a _____________________ in the cytoplasm
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Ribosome reads the ____________ to make a protein
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________________ synthesis – the manufacturing of proteins inside a cell
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_______________ – transfer RNA – involved in protein synthesis
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Within one cell, there are over ________ different kinds of tRNA molecules
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Various tRNA molecules carry _________________________ to the ribosome and
mRNA
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During protein synthesis, the nucleotide ___________________ of the mRNA
determines which amino acids to use.
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________________ – group of three bases; codes for a specific amino acid
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A protein contains at least one chain of ________________________
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________________ molecules bring amino acids to the mRNA and line them up
according to the RNA’s sequence
Heredity and the Origin of Life
The origin of modern genetics
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__________________________ – the study of inheritance (passing from parents
to offspring) of traits
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Gregor _____________________ – Roman catholic monk, highly educated;
experimented with ____________ plants
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He observed traits (_____________ and pod color) of pea plants.
___________________ – organism in which the traits remain the same for many
generations
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Example: TT or tt (both alleles the same)
___________________ – when the ancestors are not alike
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Example: Tt (both alleles not the same; a “carrier”)
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Cross – mating specific organisms to see how the traits are inherited
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Mendel’s Theories:
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Traits are controlled by __________________; each offspring has ________
factors for each trait, one from each parent)
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The same factors (alleles) _______________; different –
____________
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Each factor in the set of two is either dominant or recessive
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__________________ – has more influence on a trait
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__________________ – the “hidden” or masked factor
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Mendel discovered that when both factors were dominant (TT)
the plant showed the ________________________ trait.
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When both factors were recessive (tt), the plant showed the
__________________ trait
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When had one dominant and one recessive trait, showed the
______________________________ trait (Tt)
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__________________ – TT or tt
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__________________ – Tt
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__________________ – the physical characteristics of an organism
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__________________ – specific factors (or alleles) an organism possess
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__________________ – when pollen and eggs united; when two gametes form a
union
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Later Discoveries:
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Mendel published a paper describing his experiments and stating his
theories
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His paper sat unnoticed for _________ years, in which scientists discovered
mitosis and meiosis.
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Then scientists began to make connections as they further studied genetics.
Heredity and the Origin of Life
Genes, Chromosomes, and Heredity
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Not all chromosomes have the same number of _________________
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Chromosome number is different for different organisms, but in humans =
_________.
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Chromosomes occur in _____________; thus, humans have ________ pairs of
chromosomes
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Each member of a pair of chromosomes has the same type of
___________________ (ex. eye color and eye color)
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Each type of gene comes from each _______________ – one from mother and
one from father
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Today, Mendel’s “__________________” are called “_________________” which
are made of ___________
Punnett Squares
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_____________________squares are a visual way to understanding how
Mendel’s theories work.
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Use symbols to represent ________________ (factors)
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Symbols represent _________ genes because genes are normally paired
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However, when they form gametes, they will have one gene from each pair
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To illustrate Mendel’s cross, you can use a Punnett Square
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Practice the Punnett Square under “What do you think?” on page 99
Variations in Mendel’s Theories
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If all were either dominant or recessive, it would be easy; however, not all traits are
either dominant or recessive
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______________________ dominance – two traits combine or ______________
together to produce a different Trait
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Example: RR x WW (crossing red and white flowers)
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Because both are dominant – when they cross they will produce
________________ flowers
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_________________________ – Dominant AND recessive traits are both
expressed.
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Example: BB x WW (crossing black and white chickens) will produce
chickens with both black AND white traits.
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___________________ gene inheritance – more than two genes are responsible
for producing a single trait
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Example: scientists believe that _____________ color may be controlled by
as many as 12 different genes (which explains why all hair is different from
another!)
Inheritance of Sex Chromosomes
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Normal humans have ________ pairs of chromosomes
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The 23rd pair determines the ______ of the individual
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In females, the pair is _________
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In males, the pair is _________
The ______ chromosome is smaller than the _____ chromosome and has very few
genes
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It is the _____________ who determines the sex of the child.
Sex-linked traits
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___________________ trait – an inherited trait that has a gene on the ________
chromosome but no corresponding gene on the Y chromosome.
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In this case, an unpaired gene of the X chromosome of the male will automatically
express the trait.
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With females, only the dominant trait will express itself
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Example: red-green ________________________________
_________________ – people who have the gene for that trait but do not express
the trait themselves
Inherited Disorders
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These are _________________________ traits that are passed on through genes
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Why does God allow a person to be born with an inherited disorder?
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God has a purpose; it is NOT _________________________
Heredity and the Origin of Life
Mutations
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________________________ – any change in an organism’s genetic material
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Can occur in a ___________ base pair, a whole
_____________________________, or a whole set of chromosomes
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Most are almost always _______________________(i.e. lethal mutations –
mutations that cause death)
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Types of mutations: ______________ and _____________________
Gene Mutations
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________________ mutation – due to the change in the sequence of bases of a
segment of DNA that makes up a gene.
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When ___________________ comes to translate the mutated section of DNA, it
gets the wrong message!
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Some gene mutations affect the _________________ organism; other do not
affect the organism at all.
What is the harmful nature of gene base-pair mutations?
“THE SHY BOY SAW THE MAD DOG EAT THE FAT HAM TOO”
Somatic and Germ Mutations
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______________________ mutations (body cells – do not make gametes) – are
not passed on to future generations
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_______________________ mutations – mutations that occur in the gametes or
cells that form gametes – can be passed on to future generations
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It may not affect the organism in which it occurs, but can affect the offspring
Chromosomal Changes
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____________________ Change – involving the number of chromosomes or the
number or location of genes on a chromosome
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Can be _______________ or affect the ________________
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Does not involve the formation of ___________________, unlike gene mutations
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Chromosomes normally occur in sets
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Most people have _________ sets and are called __________________ – humans
have 23 sets (pairs)
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__________________– an unusual number of chromosomes (number of sets of
chromosomes)
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Example: down syndrome (3 of the twenty-first pair instead of 2)
Applied Genetics
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Mankind has used genetics principles for thousands of years.
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___________________________________ – choosing organisms with desirable
traits and breeding them in hopes of offspring having those traits
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__________________________ – a form of selective breeding; mating of an
organism with its close relatives, in hopes of getting purebred organisms
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___________________ – a group of organisms
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_________________________________ – another method used to produce
animals and plants with desirable traits; breeding individuals from different varieties
to produce offspring with traits from both parents
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__________________________________ – uses living organisms to make new,
more desirable organism or products
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_________________________________ – using special techniques to control the
genetic makeup of an organism
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cloning